Composite fabric combining entangled fabric of microfibers and knitted or woven fabric and process for producing same

ABSTRACT

The disclosed composite fabric, useful as a substratum for artificial leather, comprises a woven or knitted frabic and at least one non-woven fabric firmly bonded to the woven or knitted fabric, and is produced by providing a precursory sheet with two or more layers from a woven or knitted fabric and one or more fibrous webs which consist of numerous extremely fine fibers having an average diameter of from 0.1 to 6.0 microns, and uniformly impacting the fibrous web surface of the precursory sheet with numerous fluid jets ejected under a high pressure of from 15 to 100 kg/cm 2 , at a ratio of a total impact area of the fluid jets on the precursory sheet surface to an area of the precursory sheet surface to be impacted of at least 1.5, in order to allow the extremely fine fibers in the fibrous web to randomly entangle with each other and also to allow a portion of the extremely fine fibers to penetrate into the inside of the woven or knitted fabric and entangle with a portion of the fibers in the woven or knitted fabric.

The present invention relates to a composite fabric and a process forproducing the same. More particularly the present invention relates to acomposite fabric usable as a substratum sheet for artificial leather andcomprises at least one non-woven fabric constituent and a woven orknitted fabric constituent firmly bonded to form a body of a compositefabric, and a process for producing the composite fabric.

It is known that natural leather is composed of numerous collagen fiberbundles. When the back side surface of the natural leather is buffed toprovide a pile surface layer, the resultant product is a suede leather.Also, when the grain side surface is buffed, the resultant product is aso-called nubuck leather. The buffed surface of the nubuck leatherconsists of very thin collagen fiber piles.

Generally, artificial leather is produced by impregnating a substratumsheet consisting of a non-woven fabric with an elastic polymer material,for example, polyurethane and butadiene-styrene rubber. If desired, theartificial leather is buffed to convert it into a suede or nubuck-likeartificial leather. Accordingly, in order to prepare an artificialleather having a nubuck-like buffed surface, it is important thatnumerous piles consisting of extremely fine individual fibers are formedat a high density on the surface of the artificial leather, the surfaceof the artificial leather has a writing effect like that of the naturalnubuck leather, and the artificial leather has a high softness and aproper draping property. The artificial leather is also required to havea high resistance to breakage even if the artificial leather has a smallthickness of 1 mm or less.

Accordingly, there have been various atempts made to obtain anartificial leather satisfying the above-mentioned requirements. Forexample, Japanese Patent Application Publication No. 49-48583(1974)(corresponding to U.S. Pat. No. 3,932,687) discloses a non-woven fabriccomposed of fibrous bundles of fine fibers having a denier of 1.5 orless. The non-woven fabric is prepared from special composite fibers,that is, inland-in-sea type composite fibers. In the preparation of anartificial leather from this non-woven fabric, the non-woven fabric isimpregnated with an elastic polymer and, then, the fibrous bundleslocated on the surface portion of the non-woven fabric are raised toform numerous piles. However, this type of the non-woven fabric has arelatively low density because the sea components are removed from thecomposite fibers in order to convert the composite fibers into the fiberbundles. Therefore, the density of the piles formed on the artificialleather is also relatively low. In the case where the piles arerelatively short, portions of the raised surface of the artificialleather are occupied with the elastic polymeric material and, therefore,the resultant artificial leather exhibits a rough appearance and agritty feel. Furthermore, this type of artificial leather, having asmall thickness of 1 mm or less, has poor tensile and tear strengths dueto the fact that the substratum is composed of a non-woven fabric inwhich the fiber bundles are randomly entangled. Especially, the thinartificial leather has a very poor resistance to breakage at the seamsthereof, in which seams portions of the artificial leather are stronglyand frequently flexed while the artificial leather is being worn orprocessed.

Further, in the process for producing the above-mentioned conventionaltype of artificial leather, the islands-in-sea type composite filamentsare crimped by using a crimping machine, and cut to form a desiredlength of staple fibers. Then, the staple fibers are formed into arandom web by using a random webber and the random web is needle punchedto convert it into a precursory non-woven fabric. Thereafter, the seacomponent is removed from the precursory non-woven fabric so as toconvert it into a final non-woven fabric composed of the islandcomponent fiber bundles. The above-mentioned process for producing thefinal non-woven fabric involves an undesirable chemical treatment forremoving the sea component and is very complicated and expensive.

Japanese Patent Application Publications No. 41-3759(1966) and No.51-6261(1976) disclose a non-woven fabric usable as a substratum of theartificial leather. This type of non-woven fabric is composed of fibrousbundles of extreamly fine fibers or porous fibers having ahoneycomb-like cross-sectional profile. This non-woven fabric isproduced by providing composite fibers from a blend of at least twotypes of component polymers and removing at least one component polymerfrom the composite fibers after forming a precursory non-woven fabricfrom the composite fibers. This process also involves the undesirablechemical treatment for removing the component polymer and is verycomplicated and expensive.

Japanese Patent Application Publication No. 41-21475(1966) discloses anon-woven fabric usable as a substratum for suede-like artificialleather. The non-woven fabric is prepared by providing a random web froma mixture of staple fibers having a denier of 0.5 (a cross-sectionaldiameter of about 7 microns) and crimped staple fibers having a denierof 1.5, and needle-punching the random web to convert it into anon-woven fabric. However, this type of non-woven fabric can not beprovided with uniform piles in a high density and, therefore, can nothave a good writing property that is, chalk mark-forming property.Therefore, the raised artificial leather produced by using theabove-mentioned non-woven fabric as a substratum, is quite different inappearance from natural nubuck leather and has a poor density, tensileand tear strengths and dimentional stability because the substratum iscomposed of only the non-woven fabric having a poor density, tensile andtear strengths and dimensional stability.

Japanese Patent Application Laying-open No. 50-121570(1975) discloses aprocess for producing a composite fabric. In this process discontinuousextremely fine fibers are produced in a melt-blow method and aredirectly blown toward a woven or knitted fabric by action of fluid jets.In the initial stage of the blowing step, a portion of the blown fiberscan penetrate into the inside of the woven or knitted fabric. However,after the surface of the woven or knitted fabric is covered by a stratumof the extremely fine fibers, the extremely fine fibers can notpenetrate into the inside of the woven or knitted fabric and, therefore,the combination of the woven or knitted fabric with the stratum of theextremely fine fibers can not be proceeded any more. Particularly, whenthe stratum of the extremely fine fibers becomes a weight of 20 g/m² ormore, the blown extremely fine fibers are completely unable to penetrateinto the woven or knitted fabric through the stratum of the extremelyfine fibers. Therefore, the stratum of the extremely fine fibers isbonded to the woven or knitted fabric with a very poor bonding strengthof 10 g/cm or less. Further, in the stratum of the extremely fine fibersproduced in accordance with this type of process, the extremely finefibers are distributed only in two dimentions, and can not be randomlydistributed in three dimensions and entangled with each other with ahigh degree of entanglement.

That is, this type of process can not convert the stratum of theextremely fine fibers into a non-woven fabric. Accordingly, theresultant composite fabric has a poor bulkiness and recovery fromcompression. When this composite fabric is utilized as a substrate, theresultant artificial leather has an undesirable paper-like appearanceand feel, and can not provide piles formed in a high density on thesurface thereof. Also, the surface of the artificial leather has a verypoor resistance to abrasion. Therefore, this type of composite fabric iscan not be utilized for producing nubuck-like artificial leather.Additionally, when the fibers produced by the melt-blow method adhere toeach other, the resultant composite fabric has an undesirable relativelyhigh stiffness.

An object of the present invention is to provide a composite fabriccapable of providing a pile layer consisting of extremely fine fibersexisting at a high density and useful as a substratum sheet for anubuck-like artificial leather having a desirable chalk mark-formingproperty.

Another object of the present invention is to provide a composite fabricusable as a substratum sheet for artificial leather having a propersoftness and being useful as a material for clothing, and a process forproducing the same.

Still another object of the present invention is to provide a compositefabric usable as a substratum sheet for artificial leather having highresistances to breakage and abrasion, a high dimensional stability, anda process for producing the same.

The above-mentioned objects can be attained by the composite fabric ofthe present invention which comprises a woven or knitted fabricconstituent and at least one non-woven fabric constituent, in an amountof 100% or more based on the weight of said woven or knitted fabricconstituent, and consisting of numerous extremely fine individual fiberswhich have an average diameter of 0.1 to 6.0 microns and are randomlydistributed and entangled with each other to form a body of non-wovenfabric, said non-woven fabric constituent and said woven or knittedfabric constituent being superimposed and bonded together, to form abody of composite fabric, in such a manner that a portion of saidextremely fine individual fibers in said non-woven fabric constituentpenetrate into the inside of said woven or knitted fabric constituentand are entangled with a portion of fibers in said woven or knittedfabric constituent, and the bonding strength between said woven orknitted fabric constituent and said non-woven fabric constituent is atleast 30 g/cm.

The above-mentioned composite fabric can be produced by using theprocess of the present invention which comprises:

forming a fibrous web constituent by randomly massing numerous extremelyfine individual fabrics having an average cross-sectional diameter offrom 0.1 to 6.0 microns;

forming a multilayer precursory sheet by superimposing a woven orknitted fabric constituent and at least one said fibrous web constituenton each other;

jetting numerous fluid streams ejected under a pressure of from 15 to100 kg/cm² toward the surface of said fibrous web constituent of saidprecursory sheet at a ratio of a total impact area of said fluid jets onthe precursory sheet surface to an area of the precursory sheet surfaceto be impacted of at least 1.5, to convert said fibrous web into anon-woven fabric constituent in which said extremely fine individualfibers are randomly entangled with each other and to convert saidprecursory sheet into a composite fabric in which said non-woven fabricconstituent is bonded to said woven or knitted fabric constituent insuch a manner that a portion of said extremely fine individual fiberspenetrate from said non-woven fabric constituent into the inside of saidwoven or knitted fabric constituent and are entangled with a portion ofthe fibers within said woven or knitted fabric constituent. Theabove-mentioned conversions of the fibrous web into the non-woven fabricconstituent and of the precursory sheet into the composite fabric ispromoted by applying a reduced pressure of 10 to 200 mmHg onto a surfaceof said precursory sheet opposite to the fibrous web surface.

Further features and advantage of the present invention will be apparentfrom the following description, with reference to the accompanyingdrawings, wherein:

FIG. 1 is a cross-sectional model view of an internal structure ofnatural leather;

FIG. 2 is an explanatory view of a cross-sectional profile of aconventional artificial leather using fibrous bundles of extremely finefibers;

FIG. 3 is an explanatory view of a cross-sectional profile of a threeconstituent composite fabric of the present invention;

FIG. 4 is an explanatory view of a cross-sectional profile of a twoconstituent composite fabric of the present invention;

FIG. 5 is an explanatory view of a cross-sectional profile of anartificial leather produced by using a composite fabric of the presentinvention and having a pile layer;

FIG. 6 is a schematic view of an apparatus for ejecting numerous highvelocity fluid streams toward a precursory sheet;

FIG. 7 is a cross-sectional view of an orifice through which the highvelocity fluid stream is ejected;

FIG. 8 is an explanatory view of a specimen of the composite fabric ofthe present invention for testing the bonding strength between thewoven- or knitted fabric constituent and the non-woven fabricconstituent;

FIG. 9A is an explanatory view of a specimen of the composite fabric ofthe present invention, for testing the tear strength thereof;

FIG. 9B is an explanatory view of a specimen of the composite fabric ofthe present invention in a posture for testing a tear strength thereof,and;

FIG. 10 is an explanatory view of a specimen of the composite fabric ofthe present invention for testing its sewing strength.

Referring to FIG. 1, which shows the internal structure of naturalleather, numerous collagen fiber bundles, which vary in thickness, areentangled with each other. That is, the collagen fiber bundles locatedin the back side surface portion of natural leather have a relativelylarge thickness and are composed of relatively thick individual collagenfibers. However, the grain side surface portion of natural leather iscomposed of numerous very thin collagen fiber bundles and very thinindividual collagen fibers.

Accordingly, in a suede leather, which is prepared by buffing the backside surface of the leather, the buffed surface is covered with numerouspiles consisting of the relatively thick collagen fiber bundles spacedfrom each other. Compared with suede leather, in a nubuck leather, whichis produced by buffing the grain side surface of the leather, the pilescovering the buffed surface consist of very thin collagen fiber bundlesand very thin collagen individual fibers standing close to each other.Consequently, in order to obtain an artificial leather having anubuck-like buffed surface, it is important that the piles consisting ofvery thin fiber bundles and very fine individual fibers be formed in ahigh density.

Referring to FIG. 2, showing an internal structure of a conventionalartificial leather, numerous fiber bundles, having a relatively largethickness, are randomly entangled, and the piles 4 formed on the buffedsurface thereof are spaced from each other. That is, the piles areformed at a relatively low density. Accordingly, a portion of an elasticpolymer 5 impregnated between the fiber bundles 3 is sometimes notcompletely covered with the piles. This results in an artificial leatherof low quality.

The composite fabric of the present invention has a cross-sectionalstructure as explanatorily shown in FIG. 3 or 4. Referring to FIG. 3,the composite fabric 10 is composed of a woven or knitted fabricconstituent 11 embedded between an upper non-woven fabric constituent 12and a lower non-woven fabric constituent 13. In each non-woven fabricconstituent, numerous extremely fine fibers 14 are randomly entangledwith each other in three dimensions. Further, portions of the extremelyfine fibers penetrate from the non-woven fabric constituents 12 and 13into the inside of the knitted or woven fabric constituent 11, andentangle with a portion of the fibers 15 in the woven or knitted fabricconstituent 11. Accordingly, the non-woven fabric constituents 12 and 13are firmly bonded to the woven or knitted fabric constituent 11 to forma body of composite fabric.

Referring to FIG. 4, a non-woven fabric constituent 16 is superimposedon and firmly bonded to a woven or knitted fabric constituent 17 in thesame manner as mentioned above.

Referring to FIG. 5, an artificial leather 20 is composed of a compositefabric, as a substratum, impregnated with an elastic polymer 21. Thecomposite fabric has the same internal structure as that indicated inFIG. 3, except that the surface layer of the upper non-woven fabricconstituent 12 is buffed so as to form a pile layer 22. The pile layer22 consists of numerous extremely fine fibers 14 uniformly distributedin a high density. That is, the extremely fine fibers 14 are independentfrom each other but not be formed into fiber bundles.

The extremely fine fibers usable for the composite fabric of the presentinvention have an average diameter of 0.1 to 6.0 microns, whichcorresponds to a denier in a range of about 0.0001 to about 0.35. Adiameter smaller than 0.1 microns will result in a very poor tensilestrength of the resultant extremely fine fiber. Also, a diameter greaterthan 6 microns will cause the resultant composite fabric to have a poorsoftness and the resultant artificial leather to have a poor chalkmark-forming property due to a low density of the fibers located in thepile layer.

The artificial leather having a nubuck-like appearance, feel and chalkmark-forming property can be obtained by utilizing the composite fabricof the present invention, in which the non-woven fabric constituent iscomposed of extremely fine fibers with a diameter of 0.1 to 6.0 microns,preferably, 0.5 to 3.0 microns, more preferably, 1.0 to 2.0 microns.

The extremely fine fibers usable for the present invention are notlimited to a specified group of polymers as long as the polymers arecapable of forming the extremely fine fibers having the specifieddiameter. For example, the extremely fine fibers may consist of aregenerated cellulose, for instance, viscose rayon, and cuprammoniumrayon, or a synthetic polymer, for instance, polyester, polyamide,polyolefin polyacrylonitrile, a copolymer of two or more of the monomersfor forming the above-mentioned polymers or a mixture of two or more ofthe above-mentioned polymers. The polyamides involve nylon 6, nylon 66,nylon 10, nylon 11, nylon 12, a copolymer of nylon 6 with nylon 66, acopolymer of nylon 6 with nylon 10, a copolymer of nylon 6 withisophthalamide, a copolymer of nylon 6 with polyoxyethylene-di-amine, acopolymer of nylon 66 with polyoxyethylene-di-amine, a blend polymer ofnylon 66 and polyethyleneglycol, a blend of nylon 6 andpolyethyleneglycol, a blend of nylon 6 or nylon 66 and at least one ofthe copolymers described above, and an aromatic polyamide such apolymethaphenylene tetraphthalamide and poly-N-methyl-phenylenetetraphthalamide.

The polyesters may be polyethylene terephthalate, a polyethyleneterephthalate-isophthalate copolymer, a polyethyleneterephthalate-adipate copolymer, a polyethylene terephthalate-trimediatecopolymer, a polyethylene terephthalate-sebacate copolymer, apolyethylene terephthalate-succinate copolymer, apolyethylene-diethylene glycol terephthalate copolymer, apolyethylene-ethylene glycol terephthalate copolymer or a mixture of twoor more of the above-mentioned polymers.

The polyacrylic polymers may be polyacrylonitrile, a copolymer ofacrylonitrile with at least one member selected from methyl acrylate,methyl methacrylate and ethyl acrylate, or a mixture of two or more ofthe above-mentioned polymers.

The polyolefins may be polyethylene, polypropylene or a mixture ofpolyethylene and polypropylene.

The extremely fine fibers can be produced by using any of theconventional fiber-producing methods. Preferably, the extremely finefibers are produced from a thermoplastic synthetic polymer by using amelt-blow method. In order to produce a nubuck-like artificial leather,it is more preferable that the extremely fine fibers are produced frompolyethylene terephthalate by using the melt-blow method. This isbecause the polyethylene terephthalate fibers have a proper shrinkagewhich is effective for forming the pile layer having a high density.

In the composite fabric, it is desired that the extremely fine fibers inthe non-woven fabric constituent are three dimensionally entangled witheach other at a proper degree of entanglement. That is, the extremelyfine fibers should be entangled with each other to such an extent thatthe resultant non-woven fabric constituent has a density of 0.10 to 0.30g/cm³, more preferably, 0.15 to 0.28 g/cm³, and a tensile strength of0.10 to 0.30 kg/mm², more preferably, 0.12 to 0.26 kg/mm². Further, itis desired that the bonding of at least one non-woven fabric constituentwith the woven or knitted fabric constituent will result in a compositefabric having an average density of 0.15 to 0.32 g/cm³, more preferably0.18 to 0.30 g/cm³, and a tensile strength of 0.5 to 1.8 kg/mm², morepreferably, 0.7 to 1.5 kg/mm².

When a composite fabric is impregnated with an elastic polymer andbuffed on a surface thereof, a non-woven fabric constituent having adensity lower than 0.10 g/cm³ and a tensile strength lower than 0.10kg/mm² will cause the resultant artificial leather to have a paper-likeappearance and feel, and a pile layer having a poor density. Also, theutilization of a non-woven fabric constituent having a density greaterthan 0.30 g/cm³ and a tensile strength higher than 0.30 kg/mm² willresult in an artificial leather which is poor in natural leather-likesoftness, draping property and resilience.

In the composite fabric of the present invention, it is required that atleast one non-woven fabric constituent be in a total amount of at least100%, preferably, at least 150%, more preferably, 200 to 800%, based onthe weight of the woven or knitted fabric constituent. The total amountof less than 100% of the non-woven fabric constituent will result in anextremely poor resilience, compressibility and recovery from compressionand a very low bulkiness of the resultant composite fabric. Further, theexcessively small amount of the non-woven fabric constituent will causethe resultant composite fabric to exhibit the disadvantage that thenon-woven fabric constituent can not completely cover the woven orknitted fabric constituent and, therefore, a portion of the woven orknitted fabric constituent appears on the surface of the non-wovenfabric constituent layer. Such appearance of the composite fabric cannot be utilized as a substratum for the artificial leather.

In order to produce an artificial leather useful as a material forclothing, the composite fabric is required to have a high softness andresiliency. In order to meet this requirement, it is preferably that thenon-woven fabric constituent has a total weight of 50 to 200 g/m², morepreferably, 80 to 250 g/m², still more preferably, 100 to 200 g/m².

The extremely fine fibers in the non-woven fabric constituent arerequired not only to randomly and three-dimensionally entangle with eachother with a high degree of entanglement, but a portion of the extremelyfine fibers are required to penetrate into the inside of the woven orknitted fabric constituent and entangle with a portion of the fibers inthe woven or knitted fabric constituent to such an extent that both ofthe constituents are firmly bonded to each other with a bonding strengthof 30 g/cm or more.

The higher the degree of entanglement of the extremely fine fibers,penetrated from the non-woven fabric constituent, with the fibers in thewoven or knitted fabric constituent, the higher the bonding strengthbetween both the constituents. A bonding strength of 30 g/cm or more issufficient to unite the non-woven fabric constituent and the woven orknitted fabric constituent into a body of composite fabric having aproper density. In the case where the bonding strength is lower than 30g/cm, the resultant composite fabric tends to be easily divided into theseparate constituents while the composite fabric is processed, and alsotends to form a paper-like artificial leather having a poor resiliencyin spite of impregnation of the composite fabric with an elasticpolymer.

In order to provide an artificial leather useful as a material forclothing, the composite fabric to be used as a substratum is required tohave not only a high tensile strength, resiliency and bulkiness, butalso a high softness. In order to satisfy these requirements, it ispreferable that the bonding strength between the non-woven fabricconstituent and the woven or knitted fabric constituent be in a range offrom 50 to 250 g/cm, more preferably, 70 to 200 g/cm. The bondingstrength is determined in accordance with a method which will beexplained in detail hereinafter.

The woven or knitted fabric usuable as a constituent of the compositefabric of the present invention is required to have a density of weavingor knitting structure which allow the fabric to have spaces formedbetween the fibers or yarns, which spaces are large enough to receivethe portion of the extremely fine fibers penetrated from the non-wovenfabric constituent into inside of the woven or knitted fabricconstituent. That is, it is preferable that the woven or knitted fabrichas a weight of 10 to 100 g/m², more preferably, 20 to 80 g/m², stillmore preferably, 30 to 60 g/m². A very thin woven or knitted fabrichaving a weight smaller than 10 g/m² and a low density is sometimesdifficult to uniformly open without the formation of wrinkles. Theresultant composite fabric from the thin woven or knitted fabric haspoor tensile and tear strengths. Also, a very thick woven or knittedfabric with a weight of 100 g/m² and a high density is sometimesdifficult to firmly bond to the non-woven fabric due to the difficultyin the penetration of the extremely fine fibers from the non-wovenfabric into woven or knitted fabric.

The fibers in the woven or knitted fabric constituent may consist of thesame as or different from that of the extremely fine fibers. That is thewoven or knitted fabric constituent may be composed of viscose rayonfibers, cuprammonium rayon fibers, cellulose acetate fibers, polyamidefibers, polyester fibers, polyacrylic fibers, polyolefin fibers or thelike. The woven or knitted fabric constituent may be composed of amixture of two or more of the above-mentioned types of fibers, forexample, a mixture of the viscose of cuprammonium rayon fibers and thepolyamide fibers or a mixture of the polyester fibers and the polyamidefibers. The fibers in the woven or knitted fabric constituent preferablyhave a denier of 5 or less, more preferably, 0.2 to 3. If the denier ofthe fibers is excessively large, the resultant composite fabric willcreate a high stiffness in the artificial leather prepared from thecomposite fabric. Further, it is preferable that the yarns from whichthe woven or knitted fabric is formed have a total denier of 150 orless, more preferably, 100 or less, still more preferably, 70 or less.

The woven or knitted fabrics usable for the composite fabrics of thepresent invention are not restricted to a specific class of fabrics, andcan include various types of knitted fabrics, for example, plain stitchfabrics, warp knitted fabrics, warp knitted fancy fabrics, weft knittedfabrics, for instance, tricot fabrics, weft knitted fancy fabrics andlaces, as well as various types of woven fabrics, for example, plainweave fabrics, twill fabrics, stain fabrics and figured cloths.

In the preparation of the composite fabric of the present invention, afibrous web consisting of extremely fine fibers is arranged on a surfaceof a woven or knitted fabric constituent and, if necessary, anotherfibrous web consisting of the extremely fine fibers is arranged on theopposite surface of the woven or knitted fabric to provide a precursorysheet. The precursory sheet is, then, subjected to a treatment with highspeed fluid stream jets to convert the precursory sheet into a body ofcomposite fabric.

The fibrous web can be prepared from the extremely fine fibers by usingany of the conventional methods. However, it is preferable that thefibrous web be produced by using a melt-blow method or a paper-makingmethod. The melt-blow method may be the one disclosed in Japanese PatentApplication Laying-open No. 50-46972(1975). In this method, a meltedthermoplastic fiber-forming polymer is extruded through numerousspinning orifices arranged in a row into a high speed stream of a gas.The resultant discontinuous extremely fine fibers are blown onto ascreen conveyer, continuously forwarded in one direction below thespinning orifices, and accumulated on the screen conveyer to form afibrous web. In the preparation of the fibrous web in the melt-blowmethod, it is important to uniformly distribute the resultant fibers onthe screen while preventing melt-adhering of the resultant individualfibers to each other. That is, it is important, in order to easilyconvert the fibrous web into a non-woven fabric, that the individualfibers be independent from each other and free in movement in relationto each other. For the above-mentioned purpose, it is desirable that thedistance between the screen and the orifices be in a range of 20 to 60cm, more preferably, 30 to 55 cm. The fibrous web produced by themelt-blow method, is composed of extremely fine independent fibers whichdo not form fibrous bundles. In the web, the fibers are laid down alongthe surface of the web and entangled with each other in a low degree ofentanglement. However, the fibers can not substantially extend in adirection at a right angle to the web surface and, also, can notentangle with each other in this direction. The degree of entanglementof the fibers can be expressed in terms of the tensile strength anddensity of the fibrous web. Usually, the fibrous web produced in themelt-blow method, has a tensile strength of about 0.01 kg/mm² and adensity of from 0.02 to 0.05 g/cm³. Even if the fibrous web iscompressed to increase the density of the web to about 0.2 g/cm³, theresultant compressed web still has a poor tensile strength of about 0.05kg/mm². This phenomenon illustrates the fact that, in the fibrous webproduced by using the melt-blow method, the fibers are entangled witheach other at a very low degree of entanglement.

When the fibrous web, having a low degree of entanglement of the fiberstherein, is impregnated with an elastic polymer, and the resultantartificial leather is buffed, the buffed artificial leather has apaper-like appearance and feel, and a low resiliency, and is providedwith a pile layer having a very low density and a poor resistance toabrasion. Therefore, the fibrous web mentioned above is not suitable forproducing a nubuck-like artificial leather. The extemely fine fibersproduced by using the melt-blow method have a diameter of 0.1 to 6.0microns. The fine fibers may have a length of about 3 cm or more.

The fibrous web prepared by the method as mentioned above issuperimposed on the surface of a woven or knitted fabric and, ifnecessary, another fibrous web is superimposed on the opposite surfaceof the woven or knitted fabric. Otherwise the fibrous web can be formedon a surface of a woven or knitted fabric being continuously conveyed onthe conveyer screen by using the melt-blow method. In this case, it isnecessary to prevent the melt-adhering of the fibers to each other byspacing the woven or knitted fabric surface from the orifices a distanceof 20 to 60 cm.

In order to three-dimentionally entangle the extremely fine fibers inthe web with each other with a high degree of entanglement and to firmlybond the non-woven fabric constituent to the woven or knitted fabricconstituent, the precursory sheet is subjected to a treatment thereofwith numerous fluid stream jets having a high speed. By utilizing thistype of treatment, both the constituents can be firmly bonded togehtersubstantially without breakage or deterioration of the extremely finefibers in the non-woven fabric constituent and the fibers in the wovenor knitted fabric constituent, and a composite fabric having a highbonding strength and bulkiness can be obtained.

The conventional needle-punching method in unsuitable for producing thecomposite fabric of the present invention, because the needle-punchingoperation results in breakage of the extremely fine fibers and can notcause the entanglement of the extremely fine fibers with each other.Also, when the fibrous web consisting of the extremely fine fibers isneedle-punched with numerous needles each having a barb, a number of theextremely fine fibers are removed by action of the barb with the resultthat numerous holes are undesirably formed in the web. Furthermore, theneedle-punching operation causes a portion of the fibers in the woven orknitted fabric to be broken or to penetrate to the outersurface of thefibrous web through the body of the fibrous web. The needle-punchedcomposite fabric has a low mechanical strength, for example, tensilestrength, tear strength and sewing strength. Accordingly, even if thisneedle-punched composite fabric is impregnated with the elastic polymerand, then, the surface of the impregnated composite fabric is buffed,the resultant artificial leather has a paper-like appearance and feel,and a low uniformity is quality due to its poor resiliency, and bondingstrength, and a poor density of the pile layer. Therefore, theneedle-punched composite fabric can not be used as the substratum for anubuck-like artificial leather.

The treatment of the precursory sheet with the high speed fluid streamjets can be carried out by using a method as disclosed in the JapanesePatent Application No. 48-13749(1973).

Referring to FIG. 6, an apparatus 30 for ejecting numerous fluid streamjets comprises a screen conveyer 31 which rotates around a pair ofrollers 32 and 33, a pair of rollers 34 and 35 for delivery a resultantcomposite fabric 36, and a nozzle device 37 for ejecting the fluidstream jets. The nozzle device 37 has numerous orifices 37a throughwhich a fluid is ejected under a high pressure to form numerous thefluid stream jets. The ejecting orifices are arranged in at least onerow. In the apparatus as indicated in FIG. 6, the ejecting orifices arearranged in three rows and formed on three distributing pipes 38, 39 and40. These distributing pipes 38, 39 and 40 are connected to a fluidsupply source (which is not shown in FIG. 6) through a main pipe 41.

In the operation of the apparatus as shown in FIG. 6, the screenconveyer 31 is rotated in a direction of an arrow A, and a precursorysheet 42 is placed on the screen 31 in such a manner that the fibrousweb surface of the precursory sheet faces the orifices 37 and isforwarded on the screen conveyer 31 in the direction shown by an arrowB. Numerous fluid stream jets are ejected through the orifices 37 towardthe fibrous web surface of the precursory sheet 42 to convert it into acomposite fabric 36. The ejecting device 37 is reciprocally moved in adirection at a right angle to the direction in which the precursorysheet 42 is forwarded so as to uniformly impact the precursory sheetwith a number of the fluid jets ejected under a high pressure. Theprecursory sheet 42 is converted into a body of the composite fabric 36and, then, the resultant composite fabric is delivered by the deliveryrollers 34 and 35.

In the process for converting the precursory sheet into the compositefabric, it is preferable that at the same time as the fluid streamjetting operation, a reduced pressure of 10 to 200 mmHg is applied ontoa surface of the precursory sheet opposite to the fibrous web surface.This pressure reducing operation is effective to suck the fluid throughthe body of the precursory sheet together with numerous air bubblesformed in the inside of the precursory sheet. The air bubbles existingin the inside of the presursory sheet obstruct the entanglement of theextremely fine fibers with each other and with the fibers in the wovenor knitted fabric constituent. However, the air bubbles are verydifficult to remove with suction due to the extremely small size of theair bubbles which are formed in extremely small spaces formed betweenthe extremely fine fibers.

The reduced pressure to be applied onto the opposite surface of theprecursory sheet is required to be in a range of from 10 to 200 mmHg,more preferably, 20 to 100 mmHg. An excessively reduced pressure largerthan 200 mmHg tends to restrict the freedom of movement of the extremelyfine fibers in the precursory sheet, and therefore, to obstruct theentanglement of the extremely fine fibers with each other and with thefibers in the woven or knitted fabric constituent.

In the fluid stream ejecting operation, it is preferable that the fluidjet be formed from water and be in the form of a right circular rod.

FIG. 7 shows a cross-sectional profile of an orifice usable for theprocess of the present invention. In the orifice 50 as shown in FIG. 7,a cylindrical orifice 51 has an ejecting hole 52. The diameter of theejecting hole 52 is preferably in a range of from 0.06 to 0.20 mm, morepreferably, 0.07 to 0.15 mm, still more preferably, 0.08 to 0.12 mm. Inorder to eject water through the ejecting hole, it is preferable thatthe water be under a pressure of 15 to 100 kg/cm², more preferably, 20to 70 kg/cm². The higher the ejecting pressure of the water, the higherthe bonding strength and the density of the resultant composite fabric.However, an excessively high ejecting pressure will result in formationof undesirable holes in and dents on the resultant composite fabric. Theexcessively high ejecting pressure also will result in an excessivelyhigh density and stiffness of the resultant composite fabric. Also, anexcessively low ejecting pressure will result in a poor bonding strengthof the non-woven fabric constituent and the woven or knitted fabricconstituent, and in incomplete conversion of the fibrous web into thenon-woven fabric.

In the fluid stream ejecting operation, it is important that the fibrousweb surface of the precursory sheet be uniformly impacted with numerousfluid stream jets. For this purpose, it is required that the fluidjetting operation be carried out at a total impact area ratio of atleast 1.5, the term "total impact area ratio" referring to a ratio of atotal impact area of fluid jets on a precursory sheet surface to an areaof the precursory sheet surface to be impacted. For example, in the casewhere a precursory sheet is forwarded at a constant velocity in onedirection, and the location of the fluid stream jets is reciprocallymoved in a direction at a right angle to the forwarding direction of theprecursory sheet, the total impact area ratio can be calculated inaccordance with the formula (I)

    Total impact area ratio=2nNATR/WL                          (1)

wherein R represent the diameter in cm of an area where the fluid streamimpacts with the fibrous web surface, L represents the forwardingvelocity in cm/min of the precursory sheet, T represents the number ofreciprocal movements per minute of the fluid stream, n represents thenumber of fluid streams jetted onto the precursory sheet, N representthe number of jetting operations applied to the precursory sheet, Arepresents the length in cm of one movement of the fluid stream and Wrepresents the width in cm of the precursory sheet.

Only when the fluid jetting operation is carried out at a total impactarea ratio of 1.5 or more, can the fibrous web be uniformly andcompletely converted into a body of a non-woven fabric constituent andis the non-woven fabric constituent able to be uniformly and completelybonded to the woven or knitted fabric constituent. In the case of atotal impact area ratio less than 1.5, it is impossible to obtain acomposite fabric having a high enough bonding strength for producing apractically useful artificial leather. In view of the necessary degreeof density, bonding strength and entanglement of the extremely finefibers with each other of the composite fiber usable for producing theartificial leather, the fluid jetting operation is preferably performedat a total impact area ratio of 2.0 to 50, more preferably, 3.0 to 10.An extremely large total impact area ratio, for example, more than 50,will results in an excessively high density of the resultant compositefabric. Such an excessively high density will cause the resultantartificial leather to have an excessively high stiffness. Further, itshould be noted that an excessively large total impact area ratio, forexample, of more than 50, will be unable to contribute to the increaseof the bonding strength of the resulting composite fabric.

In the above-described ejecting process, the high speed fluid streamjets may directly impact on the fibrous web surface of the precursorysheet. Otherwise, a metal net may be located between the ejectingorifices and the fibrous web surface so as to weaken the impacting forceof the fluid stream jets and divide then into a plurality of thinstreams by contact of the fluid stream jets with the net. The reciprocalmovement of the fluid stream jets may be carried out along either astraight line or a curve. Otherwise, a rotational movement may be addedto the reciprocal movement of the fluid stream jets.

The ejecting operation may be carried out one or more times for oneprecursory sheet. However, it is preferable that the at least twoejecting operations be applied to one precursory sheet. That is, it ispreferable that a first ejecting operation be applied to one precursorysheet so as to strongly impact against it, and, then, a later ejectingoperation or operations be applied to the precursory sheet so as toweakly impact against it. The first strong impact operation results information of holes and dents on the surface of the fibrous web and,therefore, in formation of a rough surface of the resultant compositefabric. When such a composite fabric is converted into an artificialleather and buffed, the rough surface results in an uneven pile layer.Accordingly, it is preferable to eliminate the holes and dents formed inthe first ejecting operation by the later ejecting operation oroperations. That is, the later ejecting operation is effective forobtaining a nubuck-like artificial leather having an even pile surface,and a high and uniform density.

For the purpose of the eliminating the holes and dents formed by actionof the fluid stream jets in a proceeding jetting step, it is preferablethat each fluid stream jet in a preceding jetting step impact againstthe precursory sheet in an impact area smaller than that in a succeedingstep and the impacting force of each fluid stream jets in a precedingjetting step be at least ten times that in a succeeding step. That is,the impact area in a second or later jetting step is preferably in arange of from 3.0 to 5.0 mm².

The term "impact area", used herein, refers to a cross-sectional area ofone fluid stream jet in which the fluid stream jet impacts against theprecursory sheet surface. The impact area can be determined by usingeither of the following methods. In the case where a fluid stream jet isin the form of a cone, the impact area is calculated from the distancebetween the ejecting orifice and the precursory sheet surface, and anangle between the axis of the cone and the normal line of the cone. Inthe other method, a photograph of the impact area is taken, and theimpact area is measured on the photographic print.

The term "impacting force", used herein, refers to a force applied byone fluid stram jetted onto the precursory sheet surface and can bedetermined in accordance with the equation (2)

    F=k(PS/A)                                                  (2)

wherein F represents an impacting force, P represents a pressure inkg/cm² under which a fluid is ejected through an orifice, S represents across-sectional area in cm² of an ejecting hole of the orifice, Arepresents an impact area in cm² and k is a constant.

In the jetting process, it is preferable that the ratio of the impactingforce of each fluid stream jet in a preceding jetting step to that in asucceeding jetting step be at least ten, and more preferably, that theimpacting force satisfys the following equation (3)

    1/500≦F.sub.2 /F.sub.1 ≦1/10                 (3)

wherein F₁ represents the impacting force of one fluid stream jet in apreceding step and F₂ represents the impacting force of one fluid streamjet in a succeeding step.

If the above-mentioned ratio is smaller than 1/500, the holes and dentsformed in a preceding jetting step sometimes can not be completelyeliminated by a succeeding jetting step. Also, if the above-mentionedratio is larger than 1/10, the succeeding jetting step sometimes resultsin formation of holes and dents on the precursory sheet, while the holesand dents formed in the preceding jetting step are eliminated by thesucceeding jetting step.

The succeeding jetting step may utilize the same nozzle device asindicated in FIG. 7 or another type of a nozzle device, for example, aspraying device. However, it is necessary that the jetting operation issucceeding step be uniformly applied onto the precursory sheet.

The composite fabric of the present invention can be converted into anartificial leather by using any of the conventional methods. Forexample, the method disclosed in Japanese Patent Application PublicationNo. 37-2489(1962) can be utilized for producing an artificial leatherfrom the composite fabric of the present invention. In order to obtainan artificial leather having a high resiliency and softness, it ispreferable that the composite fabric be impregnated with 20 to 70%, morepreferably, 25 to 45%, of a rubber-like elastic polymer based on theweight of the composite fabric. The elastic polymer may be selected frompolyurethane, synthetic rubbers such as butadiene-acrylonitrile rubberand butadiene-styrene rubber, elastic polyvinyl chlorides, elasticacrylic polymers, polyaminoacids, and elastic copolymers of two or moremonomers of the above-mentioned polymers.

Also, it is preferable that after the composite fabric is impregnatedwith the rubber-like elastic polymer, the impregnated composite fabricbe shrunk at an area shrinkage of 5 to 20%, more preferably, 7 to 15%.The area shrinking process is effective for increasing the density andresiliency of the resultant artificial leather and the density of thepile layer. Therefore, even in the case where the piles are sheared toform a very thin pile layer, the surface of the resultant artificialleather can be uniformly covered by a dense pile layer consisting ofextremely fine fibers and no rubber-like elastic polymer appears on thesurface of the artificial leather. A good quality of a nubuck-likeartificial leather can be obtained from the composite fabric of thepresent invention.

The artificial leather produced from the composite fabric of the presentinvention may be raised by using any conventional raising machine, forexample, a card clothing raising machine and a so-called sander. In thecard clothing raising machine, a card clothing in which numerous fineneedles stand at a high density on a thin rubber sheet, is wound on arotatable drum. In the raising operation, the drum is rotated at a highspeed in such a manner than the top ends of the needles are brought intocontact with the surface of the artificial leather to be raised so as toconvert the individual fine fibers located in the surface portion of theartificial leather into piles.

The sander involves a drum sander in which sand paper is wound on arotatable drum of a belt sander in which an endless belt consisting of asand paper is rotated. In both types of sanders, the sand paper isbrought into contact with the surface of the artificial leather to raisethe surface.

The card clothing raising machine is suitable to form relatively longpiles and the sander is proper to produce relatively short piles.Accordingly, the raising machine suitable for obtaining a nubuck-likeartificial leather is the sander rather than the card clothing raisingmachine. However, the artificial leather may be raised by concurrentlyusing the sander and the card clothing raising machine. Further, theraised artificial leather may be subjected to a brushing or shearingprocess to improve the quality of the raised pile surface of theartificial leather.

The surface of the artificial leather may also be coated with a thinlayer of a polyurethane. In this case, a grain side layer is formed onthe artificial leather.

The composite fabric of the present invention, and the artificialleather produced from the composite fabric can be dyed or printed usinga conventional method. Further, the artificial leather may be subjectedto a crumpling process to make the artificial leather softer.

The composite fabric of the present invention also has an advantage inthat the composite fabric is useful for producing a relatively thinartificial leather which is useful as a material for clothing, due to ahigh mechanical strength, softness and draping property. Also, thecomposite fabric of the present invention has a high compressibility andrecovery from compression, because of incorporation of at least onenon-woven fabric constituent which is bulky and has a highcompressibility, and recovery from compression, into a woven or knittedfabric constituent.

In a conventional process, a thin non-woven fabric is produced byslicing a thick non-woven fabric into two or more pieces. However, theprocess of the present invention can produce a very thin compositefabric having a thickness of less than 1.0 mm, particularly, less than0.5 mm, by forming a thin fibrous web directly on a thin woven orknitted fabric and, then, converting the fibrous web into a non-wovenfabric while bonding the non-woven fabric to the woven or knittedfabric.

The composite fabric of the present invention has a smooth and evensurface. Accordingly, the artificial leather obtained from the compositefabric of the present invention also has a smooth and even surface,which is able to be uniformly dyed or printed and converted into auniform pile layer having a high density.

Also, it is important that the artificial leather obtained from thecomposite fabric of the present invention has a good chalk mark-formingproperty even when the piles in the pile layer have a relatively smalllength of 0.05 to 0.5 mm. This feature of the artificial leather issimilar to that of natural nubuck leather.

The features and advantages of the present invention are furtherillustrated by the examples set forth hereinafter, which are notintended to limit the scope of the present invention in any way.

In the following examples and comparison examples, the properties of thecomposite fabric and the artificial leather were respectively determinedin accordance with the following methods.

1. Tensile strength and breaking elongation.

Test specimens, each having a length of 20 cm and a width of 1 cm, weretaken from the fabric to be tested. The full width of the end portions,of 5 cm lengths, of the specimen was gripped, and the specimen wasstretched with an autograph until the specimen was broken. The maximumbreaking load in kg/mm² and the elongation in % at break was measured.

2. Tear strength.

Test specimens, each having a length of 10 cm and a width of 2 cm, asindicated in FIG. 8A, were taken from the fabric to be tested. Thespecimen was cut from an end thereof to a point C in FIG. 9A. The endportions A and B, of 5 cm lengths, of the specimen were gripped andstretched with an autograph, in the manner as shown by arrows in FIG.9B, until the specimen was broken. The maximum load in kg at break wasmeasured.

3. Sewing strength.

Test specimens, having a length of 10 cm and a width of 2 cm, were takenfrom the fabric to be tested. Two pieces of the specimens wereoverlapped and sewed together, in the manner indicated in FIG. 10, witha sewing machine, using a polyester sewing yarn of 50 metric count and asewing needle of 11 number count, at a stitch number of 12 stitches/3cm. The full width to the end portions, of 5 cm lengths, of the sewedspecimens was gripped and stretched with an autograph until the sewedportion was broken. The maximum breaking load in kg/cm was measured.

4. Recovery on elongation.

Test specimens, 20 cm long and 1 cm wide, were taken from the fabric tobe tested. A top end portion, of 5 cm length, of the specimen wasgripped and fixed at its full width. The lower end portion, of 5 cmlength, of the specimen was gripped and loaded with a weight of 1.0 kg.After the specimen was kept under the loaded condition for 10 minutes,the length of the specimen was measured. The specimen was released fromthe load and kept in the non-loaded condition for 10 minutes. Afterthat, the length of the specimen was again measured. The recovery onelongation was determined in accordance with the following equality:

    Percent recovery=[(L.sub.1 -L.sub.2)/(L.sub.1 -L.sub.0)]×100

wherein L₀ is the original length of the specimen before loading, L₁ isthe length of the specimen after loading, and L₂ is the length of thespecimen after releasing the load.

5. Compressibility and recovery on compression

Test specimens, 10 cm long and 10 cm wide, were taken from the fabric tobe tested. Ten pieces of the specimens were superimposed and a thinmetal plate having the same size as the specimen and a weight of 50 gwas placed on the superimposed specimens. The total thickness (t₀) ofthe superimposed specimens was measured. A weight of 10 kg was placed onthe metal plate in such a manner that the superimposed specimens wereuniformly compressed. The specimens were kept in the compressedcondition for 30 minutes. Thereafter, the total thickness (t₁) of thecompressed superimposed specimens was measured. The weight was removedand the superimposed specimens were kept in the non-weighted conditionfor 30 minutes. Thereafter, the total thickness (t₂) of the superimposedspecimens was againmeasured.

The compressibility and the recovery on compression were determined inaccordance with the following equalities.

    Compressibility(%)=[(t.sub.0 -t.sub.1)/t.sub.0 ]×100

    Percent Recovery=[(t.sub.0 -t.sub.2)/(t.sub.0 -t.sub.1)]×100

6. Density of fabric

In the determination of density of fabric, a MAEDA type of compressiveelasticity tester was used. A test specimen, 6 cm wide and 7 cm long,was placed on a disc having a diameter of 2.0 cm, and a weight of 5.0 gwas placed on the testing specimen at a load of 1.6 g/cm². Under thiscondition, the thickness of the specimen was measured. The volume in cm³of the specimen was calculated by using the thickness measured above,and the weight of g of the specimen was measured. The density of thespecimen was determined in accordance with the following equality.

    Density=(Weight/Volume)(g/cm.sup.3)

7. Bonding strength

A test specimen, 20 cm long and 1 cm wide, was taken from the compositefabric to be tested. An end portion of the specimen was split from anend thereof to a point D 10 cm far from the end along the intersurfacebetween a non-woven fabric constituent and a woven or knitted fabricconstituent, in the manner as indicated in FIG. 8. The end portions Eand F, of 5 cm lengths, of the specimen were gripped and stretched inopposite directions to each other with an autograph in the manner asindicated in FIG. 8, until the specimen was broken. The maximum load ing/cm was measured.

8. Resistance to abrasion

Test specimens, 200 mm long and 50 mm wide, were taken from the fabricto be tested. The specimens were set on a CASTOM type flat abrasiontester. The abrasion test was carried out by abrading the specimen 1,000times with sand paper of a count of AA400, under a load of 456 g, at arate of 125 cycles/minute. After completion of the abrasion test, theabrasion resistance of the specimen was evaluated in accordance with thefollowing standard.

    ______________________________________                                        Class     Remarks                                                             ______________________________________                                        5         No change                                                           4         A minor portion of surface layer is broken                          3         A major portion of surface layer is broken                          2         The inside layer is broken                                          1         A hole is made                                                      ______________________________________                                    

9. Softness

Softness was measured in accordance with the method set forth in ASTM D1388-64.

EXAMPLE 1

Polyethylene terephthalate chips were melted in an extruder and extrudedat a temperature of 320° C. through 1500 spinning orifices each having adiameter of 0.30 mm, at a extruding rate of 0.15 g/minute per orifice,into a stream of steam blown in the same direction as the extrudingdirection, at a temperature of 365° C., under a pressure of 3.5 kg/cm².The resultant discontinuous and extremely fine fivers were randomlyaccumulated on a screen conveyer moving at a constant velocity along apath 40 cm far from the orifice ends. A random fibrous web having aweight of 80 g/cm² was obtained. Based on electron microscopicobservation, the resultant fibers had an extremely small diameter of 1.5microns, which corresponds to a denier of about 0.02, and substantiallyno melt-adhering of the fibers to each other was found.

A rough interlock knitted fabric made of polyethylene terephthalatemultifilament yarn of 40 denier/36 filaments was uniformly opened andplaced on the above-prepared random web. Another random web prepared asmentioned above was placed on the knitted fabric to provide a threelayer precursory sheet. The precursory sheet was converted into acomposite fabric by using the apparatus as shown in FIG. 6. That is, theprecursory sheet was placed on the screen conveyer rotating around apair of rollers at a velocity of 10 m/minute. Numerous water streamswere ejected from the orifices toward a random web surface of theprecursory sheet under the following conditions.

    ______________________________________                                        Diameter of orifice hole 0.10 mm                                              Number of orifices       420                                                  Number of reciprocal movements of orifices                                                             200/minutes                                          Length of one movement of orifice                                                                      3.0 cm                                               Jetting pressure of water                                                                              25 kg/cm.sup.2                                       Forwarding velocity of precursory sheet                                                                1.0 m/minute                                         Width of precursory sheet                                                                              30 cm                                                Impact area per jet      0.071 mm.sup.2                                       Total impact area ratio  5.0                                                  Distance between orifice and precursory sheet                                                          3.0 cm                                               ______________________________________                                    

Simultaneously with jetting operation, a reduced pressure of 50 mmHg wasapplied to the opposite surface of the precursory sheet. Theabove-mentioned operations were applied to both the random web surfacesof the precursory sheet.

Next, both surfaces of the above-treated precursory sheet were impactedwith numerous water jets under the following conditions, while a reducedpressure of 35 mmHg was applied to the surface opposite to the surfaceonto which the water jets were ejected.

    ______________________________________                                        Diameter of orifice hole 0.10 mm                                              Number or orifices       420                                                  Number of reciprocal movements of orifices                                                             100/minute                                           Jetting pressure of water                                                                              50 kg/cm.sup.2                                       Forwarding velocity of precursory sheet                                                                2.0 m/minute                                         Impact area per jet      7.1 mm.sup.2                                         Distance between orifice and precursory sheet                                                          20 cm                                                ______________________________________                                    

The ratio of the impact force of the water jet in the first jetting stepto that in the second step was 1/50.

The resultant composite fabric had a cross-sectional structure asindicated in FIG. 3, and a high softness and resiliency. Both of thesurfaces of the composite fabric contained no holes or dents and werevery smooth and even.

The properties of the composite fabric are indicated below.

    ______________________________________                                        Weight                   200 g/m.sup.2                                        Thickness                0.78 mm                                              Density                  0.25 g/cm.sup.3                                      Tensile strength         0.95 kg/mm.sup.2                                     Tear strength            3.3 kg                                               Sewing strength          6.7 kg/cm                                            Recovery on elongation   83%                                                  Compressibility          32%                                                  Recovery on compression  81%                                                  Softness                 26 mm                                                Bonding strength         70 g/cm                                              Ratio of total weight of non-woven fabric                                     constituents to knitted fabric constituent                                    ______________________________________                                    

The non-woven fabric constituents in the composite fabric had a densityof 0.23 g/cm³ and a tensile strength of 0.21 kg/mm².

The composite fabric was impregnated with a 5% aqueous solution ofpolyvinyl alcohol and dried. Thereafter, the composite fabric wasimpregnated with 40%, based on the weight of the composite fabric, of a10% solution of polyurethane elastomer in dimethyl formamide. Theimpregnated composite fabric was immersed in a 30% aqueous solution ofdimethyl formamide so as to completely coagulate the polyurethaneelastomer in the composite fabric. Next, the composite fabric wasimmersed in hot water at a temperature of 70° C. so as to allow thecomposite fabric to shrink at an area shrinkage of 10%. The resultantartificial leather was washed, dried and, then, buffed on one surfacethereof with sand paper. The resultant artificial leather had anubuck-like pile layer consisting of extremely fine fibers and having auniform and high density. The nubuck-like artificial leather had a highsoftness and resiliency. The pile layer surface was observed by using amicroscope. The pile layer was composed of extremely fine non-bundledfibers having an average diameter of about 1.5 microns and a length of50 to 500 microns. In spite of the extremely small length of the piles,the pile layer of the artificial leather had an excellent chalkmark-forming property and no polyurethane elastomer appeared on the pilelayer surface.

The properties of the nubuck-like artificial leather are indicatedbelow.

    ______________________________________                                        Weight                285 g/m.sup.2                                           Density               0.32 g/cm.sup.3                                         Tensile strength      1.03 kg/mm.sup.2                                        Tear strength         3.5 kg                                                  Sewing strength       7.0 kg/cm                                               Recovery on elongation                                                                              90%                                                     Compressibility       25%                                                     Recovery on compression                                                                             86%                                                     Bonding strength      230 g/cm                                                Softness              32 mm                                                   Resistance to abrasion                                                                              class 5                                                 ______________________________________                                    

COMPARATIVE EXAMPLE 1

Island-in-sea type composite filaments were produced from 40% by weightof nylon 6 as an island component polymer and 60% by weight ofpolystyrene as a sea component polymer by means of a melt-spinningprocess. The composite filaments were crimped by using a stuffing boxtype crimping machine, and cut to form staple fibers having a length of35 mm. The staple fibers were converted into a cross-laid web. The webwas needle-punched at a needling density of 500 punches/cm² to form anon-woven fabric having a weight of 200 g/m². The non-woven fabric wastreated with chloroform to eliminate the sea component polymer. Thecomposite staple fibers were converted into fibrous bundles eachcomposed of 100 individual extremely fine fibers, each having a denierof 0.1.

The resultant non-woven fabric had the following properties.

    ______________________________________                                        Weight                280 g/m.sup.2                                           Density               0.13 g/cm.sup.3                                         Tensile strength      0.38 kg/mm.sup.2                                        Tear strength         1.5 kg                                                  Sewing strength       1.8 kg                                                  Recovery on elongation                                                                              40%                                                     Compressibility       52%                                                     Recovery on compression                                                                             54%                                                     Softness              38 mm                                                   ______________________________________                                    

The non-woven fabric was impregnated with the same polyurethaneelastomer and by the same method as those described in Example 1. Theresultant artificial leather was buffed to form a pile layer. Theresultant buffed artificial leather had a poor resiliency and apaper-like appearance and feel. The pile layer was composed of fibrousbundles at a low density. Accordingly, the pile layer had a poor chalkmark-forming property and a rough surface. Further, the artificialleather had a touch and appearance similar to a low grade of suedeleather.

COMPARATIVE EXAMPLE 2

A cross-laid web was produced by using a carding engine and across-layer from 9 parts by weight of polethylene terephthalate staplefibers, each having a denier of 0.5, which corresponds to a diameter ofabout 7 microns, and a shrinkage of 70%, and 1 part by weight of crimpedpolyethyelne terephthalate staple fibers having a denier of 1.5. The webwas needle-punched at a punching density of 500 punches/cm², to producea non-woven fabric having a weight of 200 g/m². The non-woven fabric wasimmersed in hot water of 80° C. so as to allow the fabric to shrink atan area shrinkage of about 50%. The shrunk non-woven fabric had thefollowing properties.

    ______________________________________                                        Weight                280 g/cm.sup.2                                          Density               0.15 g/cm.sup.3                                         Tensile strength      0.42 kg/mm.sup.2                                        Tear strength         1.8 kg                                                  Sewing strength       2.0 kg/cm                                               Recovery on elongation                                                                              56%                                                     Compressibility       47%                                                     Recovery on compression                                                                             62%                                                     Softness              47 mm                                                   ______________________________________                                    

That is, the non-woven fabric had a poor density, resiliency, mechanicalstrength and softness.

The non-woven fabric was impregnated with the same polyurethaneelastomer and in the same manner as those described in Example 1. Theresultant artificial leather was buffed with sand paper. The resultantpile layer was composed of a mixture of polyethylene terephthalatefibers having deniers of 1.5 and 0.5, and had a low density, and anuneven and rough surface. The surface had a sandy feel. When the pileswere cut into a length of 1 mm or less, the pile layer had a poor chalkmark-forming property and did not resemble the pile layer of a nubuckleather.

EXAMPLES 2 THROUGH 7 AND COMPARATIVE EXAMPLES 3

In each of Examples 2 through 5, a random web having a weight of 100g/m² was produced from fibers having a diameter as indicated in Table 1.The fibers were produced by melting nylon 6 in an extruder and extrudingthe melt at a temperature of 320° C., at a extruding rate as indicatedin Table 1, into a stream of steam, at a temperature of 360° C. ejectedunder a pressure of 4.0 kg/cm².

In each of Examples 6 and 7, nylon 6 was melted in an extruder, the meltwas extruded at a temperature of 295° C., at a extruding rate asindicated in Table 2, and the extruded melt streams were solidified andwound up at a speed of 800 m/minute. The filaments prepared were drawnat a draw ratio of 2.7 to provide nylon 6 filaments each having a denieras indicated in Table 1.

In Comparative Example 3, the same procedures as those described inExamples 6 and 7 were carried out, except that the extruding rate anddenier of the resultant drawn filaments were as indicated in Table 1.

In each of Examples 6 and 7 and Comparative Example 3, the drawnfilaments were cut to form staple fibers 5 mm long. The staple fiberswere suspended in water in an amount of 2000 times the weight of thestaple fibers. A dispersing agent consisting of polyacrylamide was addedin a concentration of 0.01% by weight to the suspension. The suspensionwas stirred so as to uniformly distribute the staple fibers in thewater. The suspension was subjected to a paper-making process using ahydroformer type paper-making machine, to produce a random web having aweight of 100 g/m².

In each of Examples 2 through 7 and Comparative Example 3, a tricotfabric consisting of nylon 6 multifilament yarn, of 70 denier/36filaments and having a weight of 60 g/m², was interposed between twopieces of the random webs obtained as described above to provide a threelayer precursory sheet. The precursory sheet was converted into acomposite fabric by using the same water-jetting process as that used inExample 1. The composite fabric was converted into a buffed artificialleather by using the same process as that employed in Example 1. Theproperties of the resultant artificial leathers of Examples 2 through 7and Comparative Example 3 are indicated in Table 1.

                                      TABLE 1                                     __________________________________________________________________________                      Property of artificial leather                                     Extruding                                                                           Average          Resistance                                             rate  diameter         to                                                     g/min per                                                                           of fiber                                                                           Appearance                                                                           Softness                                                                           abrasion                                                                            Synthetic                                        orifice                                                                             (micron)                                                                           (*)    (mm) (class)                                                                             estimation                                __________________________________________________________________________    Example                                                                       No.                                                                           2      0.10  0.1  good   26   3     good                                                        nubuck-like                                                 3      0.12  0.5  good   26   4     very good                                                   nubuck-like                                                 4      0.15  1    very good                                                                            28   5     excellent                                                   high grade                                                                    nubuck-like                                                 5      0.20  2    very good                                                                            30   5     excellent                                                   high grade                                                                    nubuck-like                                                 6      0.05  4    good   35   5     very good                                                   nubuck-like                                                 7      0.07  6    good   38   5     good                                                        nubuck-like                                                 Comparative                                                                   Example                                                                       No.                                                                           3      0.10  8    bad not like                                                                         49   5     bad                                                         nubuck                                                      __________________________________________________________________________     Note                                                                          (*)Appearance involves chalk markforming property and density of piles   

Table 1 shows that the artificial leathers produced by using fibershaving a diameter larger than 6 microns had a poor chalk mark-formingjproperty and a low density of piles. This type of artificial leatheralso had an undesirable sandy feel and, therefore, did not resemblenatural nubuck leather. The fibers having a diameter of from 0.1 to 6.0microns were useful for providing an artificial leather having a naturalnubuck leather-like appearance and feel. Especially, the fibers of 1 to2 micron diameter were useful for producing an artificial leather havinga high grade of natural nubuck leather-like appearance and feel, and avery high softness and a high resistance to abrasion.

EXAMPLE 8

Polyethylene terephthalate chips were melted in an extruder and extrudedat a temperature of 320° C., through 1500 spinning orifices, each havinga diameter of 0.30 mm, at a extruding rate of 0.25 g/minute per orifice,into a stream of steam blown in the same direction as the extrudingdirection, at a temperature of 395° C. under a pressure of 2.5 kg/cm².The resultant extremely fine fibers were accumulated on a screenconveyer moving at a constant velocity and spaced 50 cm from theorifices. The resultant random fibrous web had a weight of 80 g/m² andconsisted of numerous extremely fine fibers with an average diameter of3 microns. A two layer precursory sheet was prepared by superimposingthe above-prepared random web on a tricot fabric consisting nylon 6multi-filament yarms of 150 denier/50 filaments and having a weight of80 g/m². The precursory sheet was fed onto the screen conveyer of thewater-jetting apparatus as indicated in FIG. 6 in such a manner that therandom web surface of the precursory sheet faced the orifices. The waterjetting operation was applied to the precursory sheet under thefollowing conditions.

    ______________________________________                                        Diameter of orifice hole 0.20 mm                                              Number of orifices       420                                                  Number of reciprocal movements of orifices                                                             150/minutes                                          Length of one movement of orifices                                                                     3.0 cm                                               Jetting pressure of water                                                                              50 kg/cm.sup.2                                       Forwarding velocity of precursory sheet                                                                2.0 m/minute                                         Width of precursory sheet                                                                              30 cm                                                Impact area per jet      0.50 mm.sup.2                                        Total impact area ratio  13.4                                                 Distance between orifice and precursory sheet                                                          4 cm                                                 ______________________________________                                    

Simultaneously with the jetting operation, a reduced pressure of 150mmHg was applied to the opposite surface of the precursory sheet. Theabove-mentioned operations were repeated two times. The resultantcomposite fabric had an internal structure as indicated in FIG. 4, andwas highly soft and resilient.

The composite fabric had the following properties.

    ______________________________________                                        Weight                   160 g/m.sup.2                                        Thickness                0.50 mm                                              Density                  0.32 g/cm.sup.3                                      Tensile strength         1.4 kg/mm.sup.2                                      Tear strength            4.2 kg                                               Sewing strength          6.8 kg/cm                                            Recovery on elongation   82%                                                  Compressibility          28%                                                  Recovery on compression  78%                                                  Softness                 31 mm                                                Bonding strength         220 g/cm                                             Ratio of weight of non-woven fabric                                                                    1.0                                                  constituent to tricot fabric constituent                                      ______________________________________                                    

The non-woven fabric constituent in the composite fabric had a densityof 0.26 g/cm³ and a tensile strength of 0.30 kg/mm².

The composite fabric was impregnated with 70%, based on the weight ofthe composite fabric, of the same polyurethane elastomer and by the samemethod as those used in Example 1. The impregnated fabric was shrunk inboiling water at an area shrinkage of 7% and, then, buffed with sandpaper, to provide a nubuck-like artificial leather.

The pile layer formed on the artificial leather surface was composed ofextremely fine piles with a length of 200 microns and had an evenappearance. The pile layer also had a high density and a good chalkmark-forming property.

The resultant nubuck-like artificial leather had the followingproperties.

    ______________________________________                                        Weight                 180 g/cm.sup.2                                         Thickness              0.4 mm                                                 Density                0.45 g/cm.sup.3                                        Tensile strength       1.6 kg/mm.sup.2                                        Tear strength          4.4 kg                                                 Sewing strength        7.2 kg/cm                                              Recovery on elongation 86%                                                    Compressibility        24%                                                    Recovery on compression                                                                              84%                                                    Softness               42 mm                                                  Bonding strength       360 g/cm                                               Resistance to abrasion class 5                                                ______________________________________                                    

EXAMPLES 9A THROUGH 9D

In each of Examples 9A through 9D, two pieces of the same random webs asthat used in Example 1 were prepared. A type of woven or knitted fabricas indicated in Table 2 was interposed between two pieces of the randomwebs to prepare a three layer precursory sheet. The precursory sheet wassubjected to a first water jetting process by using an apparatus asindicated in FIG. 6 under the following conditions.

    ______________________________________                                        Diameter of orifice hole 0.15 mm                                              Number of orifices       420                                                  Number of reciprocal movements of orifices                                                             200/minutes                                          Length of one movement of orifice                                                                      3.0 cm                                               Jetting pressure         40 kg/cm.sup.2                                       Forwarding velocity of precursory sheet                                                                1.7 m/minute                                         Width of precursory sheet                                                                              30 cm                                                Impact area per jet      0.20 mm.sup.2                                        Total impact area ratio  9.9                                                  Distance between orifice and precursory sheet                                                          3.5 cm                                               ______________________________________                                    

A reduced pressure of 70 mmHg was applied onto the opposite surface ofthe precursory sheet during the water-jetting operation.

The above-mentioned operations were carried out twice on each of the websurfaces of the precursory sheet.

Next, the above-treated sheet was subjected to a second water-jettingprocess by using an apparatus as shown in FIG. 6 under the followingconditions.

    ______________________________________                                        Diameter of orifice      0.10 mm                                              Number of orifices       400                                                  Number of reciprocal movements of orifices                                                             120/minute                                           Jetting pressure         100 kg/cm.sup.2                                      Forwarding velocity of sheet                                                                           1.5 m/minute                                         Impact area per jet      3.6 mm.sup.2                                         Distance of orifice to sheet                                                                           1.8 cm                                               Ratio of impact force of water jet in second                                                           1/16                                                 step to that in first step                                                    ______________________________________                                    

The resultant composite fabric was highly soft smooth and resilient andhad the properties as shown in Table 2.

                                      TABLE 2                                     __________________________________________________________________________    Example No.          9A    9B   9C     9D                                     Woven or                                                                            Type           Knitted.sup.1                                                                       Woven.sup.2                                                                        Double.sup.3                                                                         Tricot.sup.4                           knitted                                                                             Weight         lace fabric                                                                         gauze                                                                              knitted fabric                                                                       fabric                                 fabric                                                                              (g/m.sup.2)    20    30   80     100                                    __________________________________________________________________________    Composite                                                                           Weight (g/m.sup.2)                                                                           180   190  240    260                                    fabric                                                                              Thickness (mm) 0.75  0.68 0.80   0.95                                         Density (g/cm.sup.3)                                                                         0.24  0.28 0.30   0.27                                         Tensile strength (kg/mm.sup.2)                                                               0.6   0.8  1.2    1.5                                          Tear strength (kg)                                                                           6.4   7.6  8.8    10.5                                         Sewing strength (kg/cm)                                                                      6.6   7.5  11.5   12.4                                         Softness (mm)  26    30   33     38                                           Recovery on elongation (%)                                                                   81    87   90     93                                           Compressibility (%)                                                                          32    38   42     46                                           Recovery on compression (%)                                                                  80    86   92     84                                           Bonding strength (g/cm)                                                                      160   85   55     35                                     __________________________________________________________________________     Note                                                                          .sup.1 Knitted lace fabric consisted of polyethylene terephthalate            multifilament yarns of 20 denier/15 filaments.                                .sup.2 Woven gauze was composed of viscose rayon multifilament yarns of 4     denier/30 filaments.                                                          .sup.3 Double knitted fabric was composed of nylon 66 multifilament yarns     of 70 denier/24 filaments.                                                    .sup. 4 Tricot fabric was composed of nylon 66 multifilaments yarns of 50     denier/10 filaments.                                                     

The composite fabric of Example 9B was impregnated with 50%, based onthe weight of the composite fabric, of styrene-butadiene rubber by usinga styrene-butadiene rubber latex. The impregnated fabric was immersed inboiling water so as to allow the fabric to shrink at an area shrinkageof 20%. The resultant artificial leather was buffed with sand paper. Theresultant nubuck-like pile layer was composed of extremely fine pileshaving an average length of 800 micron, and had a high density and agood chalk mark-forming property. The nubuck-like artificial leather hada weight of 290 g/m² and a density of 0.35 g/cm³.

EXAMPLE 10

Nylon 66 chips were melted in an extruder and extruded at a temperatureof 355° C., at an extruding rate of 0.15 g/minute per orifice, into anair stream blown at a temperature of 410° C. under a pressure of 3.5kg/cm². The resultant extremely fine fibers, having an average diameterof 3 microns were accumulated on a net moving at a constant velocity andspaced 30 cm from the orifice. A random web having a weight of 40 g/m²was obtained.

The same procedures as those mentioned above were carried out, exceptthat the velocity of movement of the net was one third of that in theabove-mentioned procedures. A random web having a weight of 120 g/m² wasobtained.

A plain woven fabric consisting of polyethylene terephthalatemultifilament yarns, of 40 denier/200 filaments, and having a weight of60 g/m², was interposed between the 40 g/m³ random web and the 120 g/m³random web prepared as described above. The resulting three layerprecursory sheet was subjected to a water jetting process by using anapparatus as shown in FIG. 6.

The water jetting operation was carried out under conditions detailedbelow, while a reduced pressure of 200 mmHg was applied onto the lowersurface of the precursory sheet.

    ______________________________________                                        Diameter of orifice      0.06 mm                                              Number of orifices       420                                                  Number of reciprocal movement of orifices                                                              200/minute                                           Length of one movement of orifices                                                                     3.0 cm                                               Jetting pressure         60 kg/cm.sup.2                                       Forwarding velocity of sheet                                                                           1.0 m/minute                                         Width of sheet           30 cm                                                Impact area per jet      0.032 mm.sup.2                                       Total impact area ratio  3.4                                                  Distance between orifice and sheet surface                                                             3.5 cm                                               ______________________________________                                    

The above-mentioned operations were applied to both the upper and lowersurfaces of the procursory sheet.

The resultant composite fabric had the following properties.

    ______________________________________                                        Weight                   200 g/m.sup.3                                        Thickness                1.1 mm                                               Density                  0.18 g/cm.sup.3                                      Tensile strength         0.87 kg/mm.sup.2                                     Tear strength            3.1 kg                                               Sewing strength          6.4 kg/cm                                            Compressibility          34%                                                  Recovery on compression  78%                                                  Recovery on elongation   80%                                                  Softness                 28 mm                                                Bonding properties       60 g/cm                                              Ratio of total weight of non-woven fabric                                                              2.7                                                  constituent to woven or knitted fabric                                        constituent                                                                   ______________________________________                                    

The non-woven fabric constituent had a density of 0.18 g/cm³ and atensile strength of 0.23 kg/mm². The composite fabric was impregnatedwith 20%, based on the weight of the composite fabric, of the samepolyurethane elastoner and by the same method as those used in Example1, immersed in boiling water so as to shrink it at an area shrinkage of12%, and then, buffed with sand paper. The resultant nubuck-likeartificial leather had a smooth and even pile layer consisting ofextremely fine piles having an average length of 1 mm. The pile layerhad a high density and a good chalk mark-forming property. The artificalleather was of a weight of 210 g/m² and a density of 0.25 g/cm³.

EXAMPLE 11

A random web having a weight of 150 g/m² and composed of extremely finepolyethylene terephthalate fibers, having an average diameter of 1.5microns, was prepared by the same method as used in Example 1, exceptthat the extremely fine fibers were blown toward a woven fabric placedon the net moving at a constant velocity. The woven fabric was composedof nylon 66 multifilament yarns of 120 deniers/86 filaments and had aweight of 80 g/m². The distance between the orifice and the net was 40cm.

The resultant two layer precursory sheet was subjected to awater-jetting process by using an apparatus as shown in FIG. 6 under theconditions indicated below, while a reduced pressure of 40 mmHg wasapplied to the lower surface of the precursory sheet.

    ______________________________________                                        Diameter of orifice      0.10 mm                                              Number of orifices       360                                                  Number of reciprocal movements of orifices                                                             50/minutes                                           Length of one movement of orifices                                                                     3.0 cm                                               Jetting pressure         30 kg/cm.sup.2                                       Forwarding velocity of sheet                                                                           2.0 m/minute                                         width of sheet           30 cm                                                Impact area per jet      0.071 mm.sup.2                                       Total impact area ratio  1.6                                                  Distance between orifice and sheet                                                                     3.0 cm                                               ______________________________________                                    

The above-mentioned operations were repeated three times to convert theprecursory sheet into a composite fabric.

The resultant composite fabric was highly soft and resilient and had thefollowing properties.

    ______________________________________                                        Weight                  220 g/m.sup.2                                         Thickness               1.5 mm                                                Density                 0.15 g/cm.sup.3                                       Tensile strength        1.1 kg/mm.sup.2                                       Tear strength           2.9 kg                                                Sewing strength         6.0 kg/cm                                             Recovery on elongation  78%                                                   Compressibility         33%                                                   Recovery on compression 75%                                                   Softness                26 mm                                                 Bonding strength        30 g/cm                                               Ratio in weight of non-woven                                                                          1.9                                                   fabric constituent to                                                         woven fabric                                                                  ______________________________________                                    

The non-woven fabric constituent had a density of 0.12 g/cm³ and atensile strength of 0.27 kg/mm².

The resultant composite fabric was impregnated with 40%, based on theweight of the composite fabric, of the same polyurethane elastomer andby the same method as those used in Example 1, and then, the surface ofthe non-woven fabric constituent was buffed with sand paper.

The resultant nubuck-like artificial leather had a uniform and densepile layer consisting of extremely fine piles. The artificial leatheralso had the following properties.

    ______________________________________                                        Weight                 320 g/m.sup.2                                          Density                0.25 g/cm.sup.3                                        Tensile strength       1.3 kg/mm.sup.2                                        Tear strength          3.2 kg                                                 Sewing strength        6.5 kg/cm                                              Recovery on elongation 86%                                                    Compressibility        31%                                                    Recovery on compression                                                                              81%                                                    Softness               33 nm                                                  Resistance to abrasion class 5                                                Bonding strength       210 g/cm                                               ______________________________________                                    

EXAMPLE 12

Viscose rayon yarns, each consisting of 50 individual filaments, eachhaving a diameter of 5 microns, were cut to provide staple fibers havinga length of 3 mm. 650 g of the staple fibers were suspended in 500liters of water containing 0.0002% by weight of a dispersing agentconsisting of polyacrylamide, to provide an aqueous suspensioncontaining 0.13% by weight of the staple fibers.

Two pieces of random webs, having a weight of 80 g/m², were preparedfrom the aqueous suspension by using a hydroformer type paper-makingmachine.

A twill woven fabric, which was composed of cuprammonium rayonmultifilaments yarns of 40 deniers/46 filaments and had a weight of 80g/m², was interposed between the two pieces of the random webs, preparedas mentioned above, to provide a three layer precursory sheet.

The same water-jetting process as that used in Example 1 was applied toeach random web surface of the precursory sheet while a reduced pressureof 10 mmHg was applied to the opposite surface of the precursory sheet.

The resultant composite fabric had a density of 0.30 g/cm³, a softnessof 36 mm, a bonding strength more than 250 g/cm and a ratio of the totalweight of the non-woven fabric constituents to the weight of the wovenfabric constituent of 2.0.

The composite fabric could be converted, by the same process asdescribed in Example 1, into a nubuck-like artificial leather having asmooth and dense pile layer.

COMPARATIVE EXAMPLE 4

A random web having weight of 200 g/m² and consisting of polyethyleneterephthalate fibers with an average diameter of 2.0 microns wasproduced by using the same melt-blow process as that utilized in Example1, except that the extruding rate was 0.2 g/minute per orifice, thetemperature of the steam stream was 385° C. and the blowing pressure ofthe steam was 4.0 kg/cm². The web had an area shrinkage of 40% inboiling water. The random web was subjected to the same water-jettingprocess as that used in Example 1, while a reduced pressure of 35 mmMgwas applied to the lower surface of the random web.

The resultant non-woven fabric was very soft and resilient and had thefollowing properties.

    ______________________________________                                        Density              0.20 g/cm.sup.3                                          Tensile strength     0.19 kg/mm.sup.2                                         Tear strength        1.1 kg                                                   Sewing strength      1.3 kg/cm                                                ______________________________________                                    

That is, the non-woven fabric had a poor tensile strength. The non-wovenfabric was impregnated with 40%, based on the weight of the fabric, ofthe same polyurethane elastomer and by the same method as described inExample 1, and then immersed in boiling water to shrink to an areashrinkage of 15%. Thereafter, the resultant artificial leather waswashed, dried and then raised with sand paper to form a pile layer. Theartificial leather had the following properties.

    ______________________________________                                        Weight               280 g/m.sup.2                                            Tensile strength     0.25 kg/mm                                               Tear strength        1.5 kg                                                   Sewing strength      1.7 kg/cm                                                ______________________________________                                    

In spite of its beautiful appearance and feel, the artificial leatherhad poor tensile strength, tear strength and sewing strength.

COMPARATIVE EXAMPLE 5

Polyethylene terephthalate filaments having a denier of 2 whichcorrespond to a diameter of about 15 microns, were cut to provide staplefibers having a length of 3.0 cm. Two pieces of webs having weight of 80g/cm² were produced from the staple fibers by using a carding engine. Acotton gauze fabric having a weight of 40 g/m² was interposed betweentwo pieces of the web. The resultant three-layer precursory sheet wasconverted into a composite fabric by using the same process as describedin Example 1. The resulting composite fabric had a density of 0.18 g/cm³and a softness of 62 mm.

The composite fabric was impregnated with 40%, based on the weight ofthe composite fabric, of the same polyurethane elastomer by using thesame process as described in Example 1, and then raised with sand paper.

The pile layers of the resultant raised fabric is composed of 2 denierpiles and, therefore, had a sandy feel and a rough appearance. Even whenthe pile layer was sheared to provide piles 1 to 2 mm long, the pilelayer could not exhibit a chalk mark-forming effect. The resultantfabric had the following properties.

    ______________________________________                                        Weight               280 g/m.sup.2                                            Density              0.24 g/cm.sup.3                                          Tensile strength     0.83 kg/mm.sup.2                                         Tear strength        3.1 kg                                                   Sewing strength      6.7 kg/cm                                                Softness             68 mm                                                    ______________________________________                                    

The resultant fabric could not be utilized as an artificial leather.

COMPARATIVE EXAMPLE 6

The same three-layer precursory sheet as that obtained in Example 1 wasneedle-punched at a needling density of 500 punches/cm². During theneedle-punching operation, a large amount of the extremely fine fibersare removed from the precursory sheet. After completion of theneedle-punching process, numerous holes and dents were found in theresultant composite fabric. Also, a portion of the knitted fabricconstituent appeared on the surface of the composite fabric.

The composite fabric had the following properties.

    ______________________________________                                        Weight                160 g/m.sup.2                                           Thickness             0.94 mm                                                 Density               0.17 g/cm.sup.3                                         Tensile strength      0.35 kg/mm.sup.2                                        Tear strength         1.6 kg                                                  Sewing strength       4.2 kg/cm                                               Recovery on elongation                                                                              68%                                                     Compressibility       50%                                                     Recovery on compression                                                                             62%                                                     Bonding strength      20 g/cm                                                 ______________________________________                                    

The non-woven fabric constituent had a density of 0.12 g/cm³ and atensile strength of 0.05 kg/mm².

From the fact that the above shown tensile strength of the non-wovenfabric constituent is very poor, it is obvious that the extremely finefibers in the non-woven fabric constituent are entangled at a very poordegree of a three-dimensional entanglement. Also, from the low tensilestrength of the composite fabric, it is evident that a considerableamount of fibers in the knitted fabric constituent are broken by needlesduring the needle-punching process.

The composite fabric was impregnated with a polyurethane elastomer bythe same method as that mentioned in Example 1 and then raised.

The resultant sheet had a paper-like appearance and feel and a poorresiliency due to the low degree of the three-dimensional entanglementof the fibers in the non-woven fabric constituents. Furthermore, theresultant pile layer had a low density of piles and an uneven appearanceand feel, because the pile layer was contaminated with thick pilesderived from the fibers of the knitted fabric constituent and becausethe surface of the non-woven fabric constituent was unevenly buffed dueto the existance of holes and dents formed by the needle-punchingprocess. The resultant sheet could not be utilized as an artificialleather and had the following properties.

    ______________________________________                                        Weight                210 g/m.sup.2                                           Density               0.20 g/cm.sup.3                                         Tensile strength      0.48 kg/mm.sup.2                                        Tear strength         1.9 kg                                                  Sewing strength       4.6 kg/cm                                               Recovery on elongation                                                                              72%                                                     Compressibility       45%                                                     Recovery on compression                                                                             67%                                                     ______________________________________                                    

COMPARATIVE EXAMPLES 7, 8 AND 9

A random web having a weight of 150 g/m² was produced from polyethyleneterephthalate chips by using the same melt-blow process as used inExample 1. A woven fabric consisting of nylon 66 multifilament yarns of120 denier/86 filaments and having a weight of 80 g/m² was fed onto anet spaced 15 cm (Comparative Example 7), 20 cm (Comparative Example 8),and 40 cm (Comparative Example 9) from the orifices and moving at aconstant velocity. The extremely fine fibers having an average diameterof 1.5 microns were blown onto the woven fabric so as to form atwo-layer precursory sheet.

In the precursory sheet of Comparative Example 7, the resultantextremely fine fibers melt-adhered to each other and to the fibers inthe woven fabric constituent. The precursory sheet of ComparativeExample 7 failed to be converted into a composite fabric by the samewater-jetting process as that used in Example 1.

In comparative Example 8, the melt-blown extremely fine fibersmelt-adhered to each other and to the fibers in the woven fabricconstituent, and the resultant precursory sheet was impregnated with40%, based on the weight of the composite fabric, of the samepolyurethane elastomer by using the same process as those described inExample 1, and buffed with sand paper, without applying thewater-jetting process to the precursory sheet.

The resultant sheet had the following properties.

    ______________________________________                                        Weight                320 g/m.sup.2                                           Density               0.19 g/cm.sup.3                                         Tensile strength      0.72 kg/mm.sup.2                                        Tear strength         2.4 kg                                                  Sewing strength       5.2 kg/cm                                               Recovery on elongation                                                                              65%                                                     Compressibility       8%                                                      Recovery on compression                                                                             43%                                                     Softness              63 mm                                                   Resistance to abrasion                                                                              class 2                                                 Bonding strength      100 g/cm                                                ______________________________________                                    

The sheet of Comparative Example 8 had a paper-like appearance, a stifffeel and a low resiliency. Since the pile layer had a low and unevendensity of piles, this sheet, therefore, could not be utilized as anartificial leather.

In the precursory sheet of Comparative Example 9, no melt-adhering ofthe extremely fine fibers to each other and to the fibers in the wovenfabric constituent was observed. However, the precursory sheet had avery poor bonding strength of 15 g/cm; therefore, the woven fabricconstituent could be easily separated from the non-woven fabricconstituent.

The precursory sheet was impregnated with 40%, based on the weight ofthe sheet, of the same polyurethane elastomer by using the same processas those described in Example 1, and buffed with sand paper withoutusing the water-jetting process for the precursory sheet.

The resultant sheet had a paper-like appearance and feel and thefollowing properties.

    ______________________________________                                        Weight                320 g/m.sup.2                                           Density               0.17 g/cm.sup.3                                         Tensile strength      0.67 kg/mm.sup.2                                        Tear strength         2.2 kg                                                  Sewing strength       5.1 kg/cm                                               Recovery on elongation                                                                              67%                                                     Compressibility       11%                                                     Recovery on compression                                                                             45%                                                     Softness              38 mm                                                   Resistance to abrasion                                                                              class 2                                                 Bonding strength      70 g/cm                                                 ______________________________________                                    

The bonding strength of the sheet was extremely poor because a number ofair bubbles were formed on the intersurface between the woven fabricconstituent and the web constituent. Also, the sheet had an appearanceand feel similar to those of paper and low resiliency. The pile layer ofthe sheet was extremely rough and uneven; therefore, the sheet could notbe used as an artificial leather.

What is claimed is:
 1. A composite fabric usable as a substratum sheetfor artificial leather and comprising a woven or knitted fabricconstituent and at least one non-woven fabric constituent in an amountof 100% or more based on the weight of said woven or knitted fabricconstituent, said non-woven fabric constituent having a smooth and evenouter surface and consisting of numerous extremely fine individualfibers which have an average diameter of 0.1 to 6.0 microns and arerandomly distributed and three-dimensionally entangled with each otherto form a body of non-woven fabric, said non-woven fabric constituentand said woven or knitted fabric constituent being superimposed andbonded together, to form a body of composite fabric in such a mannerthat a portion of said extremely fine individual fibers in saidnon-woven fabric constituent penetrate into the inside of said woven orknitted fabric constituent and are entangled with a portion of fibers insaid woven or knitted fabric constituent, and the bonding strengthbetween said woven or knitted fabric constituent and said non-wovenfabric constituent being at least 30 g/cm.
 2. A composite fabric asclaimed in claim 1, wherein said woven or knitted fabric constituent isinterposed between two non-woven fabric constituents.
 3. A compositefabric as claimed in claim 1, wherein one non-woven fabric constituentis superimposed on one woven or knitted fabric constituent.
 4. Acomposite fabric as claimed in claim 1, wherein said extremely fineindividual fibers in said non-woven fabric constituent are produced froma synthetic polymer by using a melt blow process and are substantiallyfree from melt-bonding to each other.
 5. A composite fabric as claimedin claim 1, wherein said extremely fine individual fibers in saidnon-woven fabric constituent are three-dimensionally entangled with eachother, and penetrate and three-dimensionally entangle with a portion ofthe fibers in said woven or knitted fabric constituent by using theaction of numerous liquid jets ejected under a high pressure toward saidnon-woven fabric constituent placed on said woven or knitted fabricconstituent.
 6. A composite fabric as claimed in claim 1, wherein saidextremely fine individual fibers consist of a polyester or a polyamide.7. A composite fabric as claimed in claim 1, wherein said non-wovenfabric constituted had a density of from 0.10 to 0.30 g/cm³ and atensile strength of from 0.10 to 0.30 kg/mm².
 8. A composite fabric asclaimed in claim 1, wherein the total weight of said at least onenon-woven fabric constituent is in a range from 80 to 300 g/m².
 9. Acomposite fabric as claimed in claim 1, wherein said woven or knittedfabric constituent has a weight of from 20 to 80 g/m².
 10. A compositefabric as claimed in claim 1, wherein the total weight of said at leastone non-woven fabric constituent is in a range of from 200 to 800% basedon the weight of said woven or knitted fabric constituent.
 11. Acomposite fabric as claimed in claim 1, wherein said bonding strengthbetween said woven or knitted fabric constituent and said non-wovenfabric constituent is in a range of from 50 to 250 g/cm.
 12. A compositefabric as claimed in claim 1, wherein said composite fabric has anaverage density of from 0.15 to 0.32 g/cm³ and a tensile strength offrom 0.5 to 1.8 kg/mm².
 13. A composite fabric as claimed in claim 1,wherein numerous piles consisting of said extremely fine individualfibers are formed on the surface of said non-woven fabric constituent.14. A composite fabric as claimed in claim 1, wherein said compositefabric is impregnated with a rubber-like elastic polymer and thenon-woven fabric constituent surface of said impregnated compositefabric is raised.
 15. A composite fabric as claimed in claim 14, whereinsaid elastic polymer is polyurethane.
 16. A composite fabric as claimedin claim 14, wherein said elastic polymer is present in an amount offrom 20 to 70%, based on the total weight of said composite fabric. 17.A composite fabric as claimed in claim 13, wherein said extremely finepiles have an average length of from 0.05 to 1.0 mm.
 18. A compositefabric as claimed in claim 1, wherein said composite fabric has an areashrinkage of from 5 to 20% in boiling water.
 19. A process for producinga composite fabric usable as a substratum sheet for artificial leather,comprising:forming a fibrous web constituent by randomly massingnumerous extremely fine individual fibers having an average diameter offrom 0.1 to 6.0 microns; forming a multilayer precursory sheet bysuperimposing a woven or knitted fabric constituent and at least onesaid fibrous web constituent on each other, jetting numerous fluidstreams ejected under a pressure of from 15 to 100 kg/cm² toward thesurface of said fibrous web constituent of said percursory sheet, at aratio of a total impact area of said fluid jets on said percursory sheetsurface to an area of said precursory sheet surface to be impacted of atleast 1.5, to convert said fibrous web into a non-woven fabricconstituent in which said extremely fine individual fibers are randomlyentangled with each other and to convert said precursory sheet into acomposite fabric in which said non-woven fabric constituent is bonded tosaid woven or knitted fabric constituent in such a manner that a portionof said extremely fine individual fibers penetrate from said non-wovenfabric constituent into the inside of said woven or knitted fabricconstituent and are entangled with a portion of the fibers within saidwoven or knitted fabric constituent, and; at the same time as said fluidstream jetting operation, applying a reduced pressure of 10 to 200 mmHgonto a surface of said precursory sheet opposite to said fibrous websurface.
 20. A process as claimed in claim 19, wherein said fluid streamjetting operation is carried out in at least two successive steps insuch a manner that each fluid stream jet in a preceding jetting stepimpacts against said precursory sheet in an impact area smaller thanthat in a succeeding step and the impacting force of each fluid streamjet in a preceding jetting step is at least ten times that in asucceeding step, in order to eliminate holes and densts formed on saidprecursory sheet surface by the action of said fluid stream jets in thepreceding step. .Iadd.
 21. An extremely fine fiber fabric usable as asubstratum sheet for an artificial leather, comprising at least onenon-woven fabric constituent having a smooth and even outer surface andconsisting of numerous extremely fine individual fibers which have anaverage diameter of 0.1 to 6.0 microns and are randomly distributed andthree-dimensionally entangled with each other to form a body ofnon-woven fabric. .Iaddend. .Iadd.
 22. A fabric as claimed in claim 21,wherein said extremely fine individual fibers in said non-woven fabricconstituent are produced from a synthetic polymer by using a melt blowprocess and are substantially free from melt-bonding to each other..Iaddend..Iadd.
 23. A fabric as claimed in claim 21, wherein thethree-dimensional entanglement of said extremely fine individual fibersis formed by using the action of numerous liquid jets ejected under ahigh pressure toward said non-woven fabric constituent. .Iaddend..Iadd.24. A fabric as claimed in claim 21, wherein said extremely fineindividual fibers consist of a polyester or a polyamide. .Iaddend..Iadd.25. A fabric as claimed in claim 21, wherein said non-woven fabricconstituent had a density of from 0.10 to 0.30 g/cm³ and a tensilestrength of from 0.10 to 0.30 kg/mm². .Iaddend..Iadd.
 26. A fabric asclaimed in claim 21, wherein the total weight of said at least onenon-woven fabric constituent is in a range from 80 to 300 g/m²..Iaddend..Iadd.
 27. A fabric as claimed in claim 21, wherein numerouspiles consisting of said extremely fine individual fibers are formed onthe surface of said non-woven fabric constituent. .Iaddend. .Iadd.
 28. Afabric as claimed in claim 21, wherein said fabric is impregnated with arubber-like elastic polymer and the surface of said impregnated fabricis raised. .Iaddend..Iadd.
 29. A fabric as claimed in claim 28, whereinsaid elastic polymer is polyurethane. .Iaddend..Iadd.
 30. A fabric asclaimed in claim 28, wherein said elastic polymer is present in anamount of from 20 to 70%, based on the weight of said fabric..Iaddend..Iadd.
 31. A fabric as claimed in claim 27, wherein saidextremely fine piles have an average length of from 0.05 to 1.00 mm..Iaddend.